Have a SQUARE WAVE in recorded file.....

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formerlyfzfile

formerlyfzfile

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Hi.
Tonight I was transferring some 2trk tapes into Sound Forge.
I used my Tascam 424mkII direct tape outs 1/2 through Delta 44 1/2 at 24bit/96k.

I hit record in SF about 2 sec. before hitting play on the 424.

In those two seconds there a perfect square wave of about -20dB amplitude on the left only.

??????????????????? How might this happen???????????

Will noise reduction work on this???

I am sure that DBX NR was off on the 424 and so was Time Code....which I dont think outputs when nothing is playing/recording from the 424 anyway.

-mike
 
You mean there's a straight line for 2 seconds, right -- not a periodic rectangle going positive and negative like a filed-off sine wave?

Perhaps you have a DC offset in that one channel only?
 
Actually its a half a square wave....

.......its a like this ( I'll try and draw it)

__ __ __ __ __
___| |___| |___| |___| |___| |___

But its only Positive amplitude....it make a noise and there is no offset visible in the actual wave file.

I have Correct For DC Offset checked in the set up......maybe I shouldn't. I was reading the other post.

-mike
 
Well, sorry about the positive/negative comment, we're talking about an amplitude graph here.

Aside from some sort of weird pulse that's "pinning" the ADC, I have no idea what might cause that...
 
Might you have ever had time code (FSK or "Smart" FSK) on that tape?
 
On this tape no time code.......

....it was just some Phish I wanted to put on disc.

I'm just using the 424 because its got good playback and is alraedy hooked up.

But I don't know WHY the signal would have no negative portion.

It SHOULD be symetrical just like you said....but its not.

Noise reduction does eliminate it though........

I did change one thing and that was to out the packet size from 4 to 3 parts in the Detla control panel.

I dont understand what it does exactly but it was suggested to be at 3 for 24/96 recording in another thread.

-mike
 
I am leaning towards the sync tone comment that AlChuck made too. Do you have anything else connected to the Delta? Any time code stuff turned on/connected?
 
Two reasons why I know its not sync tone..

1) I hit REC in CEP bfore hitting play on the 424.

2)Since I had previously been transferring 4trk masters (that kinda sounds funny now) that were both mine and a friends from long ago, before I considered why I might ever need to label and document settings and before I had ANY consistent working methods......it was all the big experiment.....I never knew wich tapes were recorded with DBX and which weren't.

So I check EVERY tape.......then label :).

-mike
 
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But I don't know WHY the signal would have no negative portion. It SHOULD be symetrical just like you said....but its not.
Click to expand...

No, it shouldn't. What you see is amplitude, not frequency. Amplitude goes from zero to maximum. In digital audio recording, the maximum value is called 0 db and amplitudes are measured relative to that in decibels, with a negative sign indicating they are below zero.
 
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